Commit 68ca4069 authored by Len Brown's avatar Len Brown
Browse files

ACPI: delete the "acpi=ht" boot option 



acpi=ht was important in 2003 -- before ACPI was
universally deployed and enabled by default in
the major Linux distributions.

At that time, there were a fair number of people who
or chose to, or needed to, run with acpi=off,
yet also wanted access to Hyper-threading.

Today we find that many invocations of "acpi=ht"
are accidental, and thus is it possible that it
is doing more harm than good.

In 2.6.34, we warn on invocation of acpi=ht.
In 2.6.35, we delete the boot option.

Signed-off-by: default avatarLen Brown <len.brown@intel.com>
parent 4c81ba49

Documentation/kernel-parameters.txt

+1 −2
Original line number Diff line number Diff line
@@ -143,11 +143,10 @@ and is between 256 and 4096 characters. It is defined in the file 


	acpi=		[HW,ACPI,X86]

			Advanced Configuration and Power Interface

			Format: { force | off | ht | strict | noirq | rsdt }

			Format: { force | off | strict | noirq | rsdt }

			force -- enable ACPI if default was off

			off -- disable ACPI if default was on

			noirq -- do not use ACPI for IRQ routing

			ht -- run only enough ACPI to enable Hyper Threading

			strict -- Be less tolerant of platforms that are not

				strictly ACPI specification compliant.

			rsdt -- prefer RSDT over (default) XSDT

arch/ia64/include/asm/acpi.h

+0 −1
Original line number Diff line number Diff line
@@ -94,7 +94,6 @@ ia64_acpi_release_global_lock (unsigned int *lock) 
#define acpi_noirq 0	/* ACPI always enabled on IA64 */

#define acpi_pci_disabled 0 /* ACPI PCI always enabled on IA64 */

#define acpi_strict 1	/* no ACPI spec workarounds on IA64 */

#define acpi_ht 0	/* no HT-only mode on IA64 */

#endif

#define acpi_processor_cstate_check(x) (x) /* no idle limits on IA64 :) */

static inline void disable_acpi(void) { }

arch/x86/include/asm/acpi.h

+0 −2
Original line number Diff line number Diff line
@@ -85,7 +85,6 @@ extern int acpi_ioapic; 
extern int acpi_noirq;

extern int acpi_strict;

extern int acpi_disabled;

extern int acpi_ht;

extern int acpi_pci_disabled;

extern int acpi_skip_timer_override;

extern int acpi_use_timer_override;
@@ -97,7 +96,6 @@ void acpi_pic_sci_set_trigger(unsigned int, u16); 
static inline void disable_acpi(void)

{

	acpi_disabled = 1;

	acpi_ht = 0;

	acpi_pci_disabled = 1;

	acpi_noirq = 1;

}

arch/x86/kernel/acpi/boot.c

+3 −16
Original line number Diff line number Diff line
@@ -62,7 +62,6 @@ EXPORT_SYMBOL(acpi_disabled); 
int acpi_noirq;				/* skip ACPI IRQ initialization */

int acpi_pci_disabled;		/* skip ACPI PCI scan and IRQ initialization */

EXPORT_SYMBOL(acpi_pci_disabled);

int acpi_ht __initdata = 1;	/* enable HT */



int acpi_lapic;

int acpi_ioapic;
@@ -1460,9 +1459,8 @@ void __init acpi_boot_table_init(void) 


	/*

	 * If acpi_disabled, bail out

	 * One exception: acpi=ht continues far enough to enumerate LAPICs

	 */

	if (acpi_disabled && !acpi_ht)

	if (acpi_disabled)

		return; 



	/*
@@ -1493,9 +1491,8 @@ int __init early_acpi_boot_init(void) 
{

	/*

	 * If acpi_disabled, bail out

	 * One exception: acpi=ht continues far enough to enumerate LAPICs

	 */

	if (acpi_disabled && !acpi_ht)

	if (acpi_disabled)

		return 1;



	/*
@@ -1513,9 +1510,8 @@ int __init acpi_boot_init(void) 


	/*

	 * If acpi_disabled, bail out

	 * One exception: acpi=ht continues far enough to enumerate LAPICs

	 */

	if (acpi_disabled && !acpi_ht)

	if (acpi_disabled)

		return 1;



	acpi_table_parse(ACPI_SIG_BOOT, acpi_parse_sbf);
@@ -1550,21 +1546,12 @@ static int __init parse_acpi(char *arg) 
	/* acpi=force to over-ride black-list */

	else if (strcmp(arg, "force") == 0) {

		acpi_force = 1;

		acpi_ht = 1;

		acpi_disabled = 0;

	}

	/* acpi=strict disables out-of-spec workarounds */

	else if (strcmp(arg, "strict") == 0) {

		acpi_strict = 1;

	}

	/* Limit ACPI just to boot-time to enable HT */

	else if (strcmp(arg, "ht") == 0) {

		if (!acpi_force) {

			printk(KERN_WARNING "acpi=ht will be removed in Linux-2.6.35\n");

			disable_acpi();

		}

		acpi_ht = 1;

	}

	/* acpi=rsdt use RSDT instead of XSDT */

	else if (strcmp(arg, "rsdt") == 0) {

		acpi_rsdt_forced = 1;

arch/x86/lguest/boot.c

+0 −1
Original line number Diff line number Diff line
@@ -1391,7 +1391,6 @@ __init void lguest_init(void) 
#endif

#ifdef CONFIG_ACPI

	acpi_disabled = 1;

	acpi_ht = 0;

#endif



	/*

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